Lubricating oil



a with resultant engine failure.

Patented Dec. 7, 1943 LUBRICATING OIL Richard G. Clarkson, WilmlngtomDeL, aalignor to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporatlon of Delaware N Drawing.

Application September 18, 1942,

Serial N0. 458,823

l2 Claims. (01. 252-51) This invention relates to lubricating oils and more particularly to lubricating oils which con-' tain or tend to form sludge and also contain compounds to inhibit the separation of insoluble sludge from the oils. v

Lubricating oils deteriorat under'the conditions to which they are expo d in internal combustion engines. This deterioration is accompanied by the formation of organic acids and by the separation-of insoluble sludge. The organic acids tend to corrode alloy bearings, and the insoluble sludge which separates fouls the internal surfaces oi the engine. Eventually, as more sludge separates, the oil lines become clogged and delivery of the oil to moving parts is prevented,

have been suggested which, it is claimed, will lengthen the period of useful service of a lubri'cating oil before harmful deterioration becomes evident. Other agents have been suggested which, it is claimed, will protect alloy bearings against corrosion by organic acids. In compounding heavy-duty lubricating oils, especially for Diesel engines, it has recently. ,been found desirable to add compounds which have detergent and dispersive properties. Such compounds tend 'to prevent the fouling of engine part and filters, and result in much cleaner engines. They are believed to maintain the sludge, formed as the oil deteriorates, in a state of colloidal dispersion. In some cases, they display suflicient detergent action to remove existing deposits from a previously fouled engine. A number of. compounds, which are claimed to display detergent and dispersive properties, have been disclosed in the prior art.

There compounds are all organo metallic com-- pounds of various types and in general have been found to accelerate corrosion of alloy bearings.

(S. A. E. Transactions, April, 1941, ages 128-137 4 p 49 played in accordance with my invention, may be Crankcase Oils for Heavy Duty Service," by H. R. Wolf) It is an object of the present invention to provide lubricating oils having a materially decreased tendency to separate and deposit sludge. Another object is to-treat lubricating oils, normally tending to deposit insoluble sludge, to inhibit the sep- 1 aration and deposition of the insoluble sludge.

-A further object is to provid a method for inhibiting the deposition of sludge on internal Various agents still further object is to provide lubricating oils which are particularly adapted for use in heavyduty service over longer periods of time in an internal combustion engine with less fouling of 5 the engine. Other objects are to provide new compositions of matter. Still other objects will appear hereinafter.

The above and other objects may be accom- Dlished in accordance with my invention which comprises incorporating in a mineral lubricating oil, normally tending to separate and deposit insoluble sludge, a small proportion of an acylated :polyamine containing at least 14 carbon atoms in which each acyl group is derived from a naph- 15 thenic acid and the polyamine group is derived from an aliphatic polyamine containing at least 2 primary amino groups separated by at least 2 carbon atoms. 1 have found that such acylated polyamines are very eflective for preventing the separation of insoluble sludge from lubricating oils, being more e'ifective than compounds which have heretofore been proposed for this purpose.

In addition, such acylated polyamines do not have any tendency to promote the corrosion of sensitive bearing metals and hence my compounds do 5 troleum lubricating oils employed in heavy-duty service where the tendency for the oils to form insoluble sludge and' for such sludge in deposit j upon and foul the engines is particularly severe.

The acylated-polyamines, which are to be emrepresented by.-the general formula a-mL-x-mL-B group, B represents hydrogen or a naphthenic acid acyl group, X is an aliphatic group containing at least two carbon atoms and A+X+B contain a total of at least 14 carbon atoms.

combustion engine during operation thereof. A ,50 i i in waded separate carbon atoms in the aliphatic group represented by X.

The acyl group or groups are derived from naphthenic acids. The naphthenic acids occur naturally in crude petroleum and are usually obtained therefrom in the form of mixtures of acids of different molecular weights. They are cyclic, generally containing a five-membered carbocyclic ring with the carboxyl group mainly on the end of an alkyl side chain. Theyare distinguished from the natural fatty acids and the fatty acids,

obtained by the oxidation of, paraflln wax and the, I

like, in that such products are open chain carboxylic acids.

Amides, wherein the acyl groups are derived 5 from the open chain fatty acids, are soluble in lubricating oils to a very limited extent only. On the other hand, the acylated polyamines or amides of my invention, in which the acyl groups are derived from naphthenic acids, are quite soluble in lubricating oils and can be readily dissolved in theoils in the amounts desired. Therefore, I generally prefer to employthe -amides derived from the naphthenic acids. By the term naphthenic acid, I mean those derived from petroleum. The naphthenic acids are ordinarily obtained as mixtures and appear on the market as such. Such commercial mixtures of naphthenic acidsare particularly desirable for preparing the acylated polyamines to be employed in accordance with my invention.

The polyamine group in the acylated polyamines or amides, which may-be employed in accordance with my invention, may be derived 35 from any open chain aliphatic polyamine con-'- taining at least two primary amino groups separated by at least two carbon atoms. The polyamine group may be represented by the formula 4 4 wherein the two nitrogens represent the nitrogens of the two primary amino groups and X represents an open chain divalent aliphatic group of at least two carbon atoms. The aliphatic chain may contain internal linkages such as -'0, 50

S -SS; -SO, SO2-,- NH and -NR- wherein R represents an, aliphatic group or ,a naphthenic acid acyl group. Preferably, the polyamine group is derived from an alkylene diamine. By the terms alkylene polyamine and alkylene diamine, I mean that such poly.- amines or diamines consist of the elements carbon, hydrogen and nitrogen solely, the nitrogen being present in amino groups. Also preferably, 60

the two primary amino groups areseparated by only two carbon atoms as in ethylene diamine, 1,2-propylene diamine and 2,3-butylene diamine.

Particularly suitable acylated polyamines have 6 been prepared from Ethylene diamine. two-momma: (2) c n 1,2-propylene dlaminaHzN HO :NH: 7

(a) (4) Diethylene trlamine, mivomcmnnomonmm methylene tetrae, EQNCHgCHgNHCHzCTfiWHCHzCHrNHg.

Dl-(y-nmino propyl)- I methyl amine, HzNCHzCHzCHzNCHzCHzCHzNH; Dl-(fi-ammo ethyD-suliidc, HaNCHICHZSCHgCHgNH:

Other polyamines, which may be employed for producing suitable acylated polyamines, are- CHr-CH-C H-CH:

NH1 NH 2,3-butylene diamine CHs-CH-QH-C3H1 NE: NH: 2,3-hexylene dial-nine mNomomo omcnmn, 6,fl'-Di(aminoethyl) ether H;NCH:CH:0 CHgCHaNHCHzCHzNH: B-Amino ethyl amino ethyl-B-amino ethyl ether CH; on:

The acylated polyamines, which are to be employed in accordance with my invention, may

contain one or more acyl groups for each polythe particular amide and on the amount of sludge in the oil and the amount of sludge normally formed by the oil under the particular conditions polyamine and, particularly, from an alkyle'ne 55 1o Hexamethylene diamlne HQNCHQCHQCHrCHCHQCHlNH:

- under which it is to be employed. Usually, the 40 I amidewill be employed within the range of from about 0.1% to about 5% by weight based on the oil. Larger amounts may be necessary in extreme cases. 1

The acylated polyamines or amides of my in- 5 vention may be prepared by the action of the naphthenic acid, its halide, nitrile or ester on the polyamine, by methods which are well known to the art, The preferred method involves mixing the theoretical equivalents of acid and amine "and heating to from about 180 C. to about 190 C. under an atmosphere of nitrogen until the theoretical amount of water has distilled out.

The crude reaction mixtures, as thus obtained, are quite suitable for use in accordance with my invention withoutseparating or purifying the amide.

The following test has been devised to allow rapid evaluation of sludge dispersant properties of various addition agents in oils.

A 75 cc. sampleof commercial S. A. 20 oil,

containing a definite concentration of the additive being tested and 2.0% of naphthenic acids,

was heated to 150 C. Two cos. of a benzene soluble sludge extract were added and the solution 5 was stirred for two minutes.

A gram sample of the sludge-oil mixture was weighed into a 100 cc. centrifuge tube and, after cooling to room temperature, cos. of A. B. T. M. naphtha were added, the tube stop pered and shaken, and then centrifuged 45 minutes. The volume of separated sludge was observed and recorded. Ineach set of tests, one

sample of control oil, containing naphthenic acid and sludge but no dispersant additive, was included.

The eflic'iency of a given additive as a slilixrlige dispersant was calculated from the form :the hot oil roughly duplicates the formation of sludge in an oil in use. The purpose oi the dilution with A. S. T. M. naphtha is to reduce the viscosity of the medium in order to permit-eiiec- .tive separation of sludge by centrifuging.

The following table illustrates the eiiective dis persion of sludge in oil containing compounds of our invention.

' Table I Additive, amide tom- Per cent Contact Ratio additive 133353; Amino Acid sludge Ethylene diamine-.- Naphthenie. 2 85-98 1 72-90 .5 40-76 .25 32-33 1,2-propylene di- .-...do 2 ,60-96- amine. 1 44-88 .5 44437 Hexamethylene dido 2 78-74 amino. 1 5 6g Dietbyiene triamine 2 50 Do -.do 2 84 Do. -i -do 2 79 Triethyienetetra- -.--do 2 8i mine.

. D0. .do-... 2 87 Di-( -aminopropyb- ..do 2 53 methyl amine. Di- :minoethyD- do..-.-.. 1:2 2 72 I Part of naphthenic acid may not have formed amide but only ammonium soap.

In the above table, the numbers, under ratio, indicate that the amides employed were those obtained from 1, 2, 3 and 4 moles of the acid and 1 mole of the polyamine. The naphthenic acid amides were prepared from a commercial refined mixture of napthenic acids having an acid number of 230-240 and was composed of naphthenic hibitors, oiliness agents, extreme pressure agents It om lie-understood that the specific embodiments disclosed hereinbefore and the tests thereon are given ior illustrative purposes only. It,

will be apparent that many variations and modifications can be made inthe compounds and the conditions and-proportions employed without departing from the spirit or scope of my invention. The oil compositions may contain other addition agents which perform other-iunctions, such as pour point depressants, corrosion inand the like. Accordingly, I intend to cover my V invention broadly as in the appended claims;

I claims. 1. A lubricant'comprising a mineral lubricating oil, normally tending to separate and deposit insoluble sludge, and a small proportion, suffl cient to inhibit deposition of the sludge, of an acylated polyamine containing at least 14 carbon atoms in which each acyl group is derived ing oil, normally tending to separate and deposit insoluble sludge, and a small proportion, sufllcient to inhibit deposition of the sludge, of an acylated polyamine containing at least 14 carbon atoms in which each acyl group is derivedfrom a naphthenic acid and the pqlyamine group is derivedfrom .analkylene polyamine containing at least two primary amino groups separated by at least 2 carbon atoms. 5 3. A lubricantcomprising a'. mineral lubricating oil, normally tending to separate and deposit insoluble sludge, and a small proportion, suiiicient to inhibit deposition of the sludge, oi

' an acylated diamine containing at least 14 carbon acid amides are oily substances having a high degree of solubility in petroleum oils. Another naphthenic acid amide was prepared from 1 mole of 1,2-propylene diamine and 2 moles 01' a commercial mixture of refined naphthenic acids having' an acid number of 125 and an apparent average of approximately 30 carbon atoms. This last 2% concentration in the oil, gave a dispersion of the sludge.

The acylated polyamines or amides of my in,

vention have no substantial pour depressant compound, when subjected to the above test in v properties. This is illustrated by'the results of tests given in the following Table II:

atoms in which each acyl group is derived from a naphthenic acid and the diamine group is derived from an aliphatic diamine containing two primary amino groups separated by at least 2 carbon atoms.

4. A lubricant comprising a mineral lubricating oii, normally tending to separate and deposit insoluble sludge, and a small proportion, sufilcient to inhibit deposition of the sludge, of an acylated diamine containing at least 14 carbon atoms in which each acyl group is derived from a naphthenic acid and the diamine group is derived from f an aliwlene diamine containing two primary amino groups separated by only 2 carbon atoms.

5. A lubricant comprising a mineral lubricating oil, normally tending to separate anddeposit insoluble sludge, and a small proportion, sufficient to inhibit deposition of the sludge, of an acylated ethylene diamine containing at least 14 carbon atoms iii which each acyl group is derived from a naphthenic acid and the diamine group is derived from ethylene diamine.

6. A lubricant comprising a mineral lubricating oil, normally tending to separate and deposit insoluble sludge, and a small proportion, sufiicient to inhibit deposition .of the sludge, of an acylated propylene diamine containing at least 14 carbon atoms in which each acyl group is derived Irom a. naphthenic acid and the diamine group is derived from 1,2-propylene diamine.

7. A lubricant comprising a mineral lubricating oil, normally tending to separate and deposit insoluble sludge, anda small proportion, suilicient to inhibit deposition of the sludge, oi." a polyacylated polyamine containing at leastl'4 carbon atoms in which each acyl group is derived froma naphthenic acid and'the polyamine group is derived from an aliphatic polyamine containing at least two primary amino groups separated by at least 2 carbon atoms.

8. A lubricant comprising a minerallubricati'ng oil, normall tending to separate and deposit insoluble sludge, and a small proportion, suflicient to inhibit deposition of the sludge, of a diacylated diamine containing at least '14 carbon atoms in which each acyl group is derived :from a naphthenic acid and the diamine group is derived from an aliphatic diamine containing two aasaovc rived from a naphthenic acid and the diamine group is derived from ethylene diamine.

11. A lubricant comprising a mineral lubricat- 'ing oil, normally tending to separate and deprimary amino groups separated by at least 2 carbon atoms. l

9. A lubricant comprising a mineral lubricating oil, normally tending to separate and deposit insoluble sludge, and a small proportion, suflicient to inhibit deposition of the sludge, of a posit insoluble sludge, and a small proportion. sufflcient to inhibit deposition of the sludge, of a diacylated propylene diamine containing at least 14 carbon atoms in which each acyl group is derived from'a naphthenic acid and the diamine group is derived from 1,2-propy1ene diamine.-

12. A lubricant comprising a mineral lubricating oil, normally tending to separate and deposit insoluble sludge, and a small proportion, suflidiacylated diamine containing at least 14 carbon 20 cient to inhibit deposition of the sludge, of -a diatoms in which each acyl group is derived from a naphthenic acid and the diamine group is de I rived from an alkylene diamine containing two primary amino groups separated by at least2 carbon atoms.

10. A lubricant comprising a mineral lubricat- Y 'acylated triethylene tetramine containing at least 14 carbon atoms in which each acyl group is derived from a naphthenic acid and the amine group is derived from triethylene tetramine.

RICHARD G. CLARKSONQ 

